从Android中的自定义列表适配器调用活动方法？

Question

On button click I am trying to send some data to my php script using the google's volley library. The method for sending the data is inside an Activity and I have written an interface to call the method from the custom list adapter.

The following is my adapter code:

public class RoleList extends ArrayAdapter<String> {

    public static final String DELETEUSERINFO = VirtualMachineIp.VMIP_ADDRESS.trim() + "goldmine/getuserinfo.php";
    public static final String KEY_NAME = "name";
    public static final String KEY_ROLE = "role";
    private ArrayList<String> name;
    private ArrayList<String> username;
    private ArrayList<String> password;
    private ArrayList<String> role;
    private Activity context;

    public int getPos() {
        return pos;
    }

    public void setPos(int pos) {
        this.pos = pos;
    }

    int pos;

    public boolean isDelPressed() {
        return delPressed;
    }

    public void setDelPressed(boolean delPressed) {
        this.delPressed = delPressed;
    }

    boolean delPressed;

    private onDelCallback listener;

    public RoleList(Activity context, ArrayList<String> name, ArrayList<String> username, ArrayList<String> password, ArrayList<String> role, onDelCallback listener) {
        super(context, R.layout.role_list, name);
        this.context = context;
        this.name = name;
        this.username = username;
        this.password = password;
        this.role = role;
        this.listener = listener;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = context.getLayoutInflater();
        final View listViewItem = inflater.inflate(R.layout.role_list, null, true);
        final TextView textViewName = (TextView) listViewItem.findViewById(R.id.tv_empname);
        final TextView textViewusername = (TextView) listViewItem.findViewById(R.id.tv_empusername);
        final TextView textViewPass = (TextView) listViewItem.findViewById(R.id.tv_emppassword);
        final TextView textViewRole = (TextView) listViewItem.findViewById(R.id.tv_emprole);
        Button edit = (Button) listViewItem.findViewById(R.id.btn_editRole);
        Button delete = (Button) listViewItem.findViewById(R.id.btn_delRole);


        delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                setDelPressed(true);
                name.remove(position);
                username.remove(position);
                password.remove(position);
                role.remove(position);
                listener.deleteuser(position);
                notifyDataSetChanged();
                setPos(position);

            }
        });
        edit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d("Emp Info", name.get(position) + " " + username.get(position) + " " + password.get(position) + " " + role.get(position));

                final Dialog dialog = new Dialog(getContext());
                dialog.setContentView(R.layout.userreg);
                dialog.setTitle("Edit Employee " + name.get(position) + " details");
                final String[] arraySpinner = new String[]{"Manager", "Stockist", "Cashier", "Accountant"};
                dialog.setCancelable(false);
                dialog.setCanceledOnTouchOutside(false);
                final EditText emp_name = (EditText) dialog.findViewById(R.id.editTextName);
                final EditText emp_uname = (EditText) dialog.findViewById(R.id.editTextUserName);
                final EditText emp_pw = (EditText) dialog.findViewById(R.id.editTextPassword);
                final Spinner emp_role = (Spinner) dialog.findViewById(R.id.spinner_role);
                final TextView textRole = (TextView) dialog.findViewById(R.id.tv_selected_role);
                ArrayAdapter<String> adapter = new ArrayAdapter<String>(getContext(), android.R.layout.simple_spinner_item, arraySpinner);
                emp_role.setAdapter(adapter);
                emp_role.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                    @Override
                    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                        Toast.makeText(getContext(), "Role Selected is " + arraySpinner[position], Toast.LENGTH_SHORT).show();

                        String employee_role = arraySpinner[position];
                        textRole.setText(employee_role);

                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> parent) {

                    }
                });


                emp_name.setText(name.get(position));
                emp_uname.setText(username.get(position));
                emp_pw.setText(password.get(position));
                emp_role.setSelection(position);

                Button buttoncancel = (Button) dialog.findViewById(R.id.buttonCancel);
                buttoncancel.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        dialog.dismiss();
                    }
                });

                Button buttonChange = (Button) dialog.findViewById(R.id.buttonRegister);
                buttonChange.setText("Change");
                buttonChange.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        textViewName.setText(emp_name.getText().toString());
                        textViewusername.setText(emp_uname.getText().toString());
                        textViewPass.setText(emp_pw.getText().toString());
                        textViewRole.setText(textRole.getText());
                        dialog.dismiss();

                    }
                });


                dialog.show();
            }
        });


        textViewName.setText(name.get(position));
        textViewusername.setText(username.get(position));
        textViewPass.setText(password.get(position));
        textViewRole.setText(role.get(position));

        return listViewItem;
    }

    public interface onDelCallback {
        void deleteuser(int pos);
    }



}

The following code should ideally get called when the button inside the list is pressed:

@Override
    public void deleteuser(final int pos)
    {
        StringRequest stringRequest = new StringRequest(Request.Method.POST, DELETEUSERINFO, new Response.Listener<String>() {
            @Override
            public void onResponse(String response)
            {
                String resp = response.toString().trim();
                if (resp.equals("UNABLE TO DELETE USER"))
                {
                    Log.d("UNABLE TO DEL",resp);
                }else if (resp.equals("USER DELETED SUCCESSFULLY"))
                {
                    Toast.makeText(UserRegistration.this, "USER DELETED SUCCESSFULLY", Toast.LENGTH_SHORT).show();
                }

            }
        },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {

                        Toast.makeText(UserRegistration.this, "Please check your internet connection", Toast.LENGTH_LONG).show();
                    }
                }){

            @Override
            protected Map<String, String> getParams() throws AuthFailureError {
                Map<String, String> params = new HashMap<>();
                params.put(KEY_NAME, employee_name.get(pos));
                params.put(KEY_ROLE,employee_role.get(pos));
                return params;
            }
        };
        RequestQueue rq = Volley.newRequestQueue(this);
        rq.add(stringRequest);
    }

I set the adapter inside parseUserinfo() which runs on response of getUserinfo() which I call inside onCreate().getUserinfo() is used to request data from the remote server.

This is how I set the adapter:

 RoleList roleList = new RoleList(UserRegistration.this, employee_name, emp_username, emp_password, employee_role,UserRegistration.this);
 userList.setAdapter(roleList);

I want to know if I am calling the adapter in the right place. Do I need to call it again?

Any help or suggestion is appreciated. Thank you.

Answer 1

There are certain ways through which u can call your activity method from adapter:

1. when u create an constructor of adapter at that time you can pass your activity object in its parameters and then use that object in your adapter.

2. If u create a interface in adapter you must implement that interface in your respective activity and then you can pass your activity object through adapter constructor and can use your required method.

Answer 2

public RoleList(Activity context, ArrayList name, ArrayList username, ArrayList password, ArrayList role, onDelCallback listener) { } In the above constructor u must pass the Respective Activity object for example MyActvity mActivity rather then passing the generic Activity object. As i hope your method is available in MyActvity class and also considering you had implement the interface on MyActvity class.

Answer 3

You can perform your delete task of your activity in adapter like this

delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                UserRegistration act = (UserRegistration) context;
                act.deleteuser(position);
            }
        });